Unicef says 168 children have died in the violence in Gaza, as Israel has been told it may be guilty of war crimes.
The UN has said Israel is not doing enough to protect Palestinian civilians, and it also criticised Hamas for "indiscriminate attacks" on Israel.
Up to 650 Palestinians have died over the past 15 days, nearly a third of them are children.
More than 1,100 children have also been injured.
Unicef's June Kunugi in Gaza says children are bearing the brunt of the conflict.
She said: "We see children under severe distress, they are traumatised, they are seeing things that no child should have to see.
"They are seeing deaths and traumatic experiences, losing their homes, they are also having to fear for their own safety when they are trying to move from one place to another."